1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

CleanCache Merged Into The Linux Kernel

Linux Kernel

Published on 26 May 2011 03:18 PM EDT
Written by Michael Larabel in Linux Kernel
13 Comments

While the first Phoronix benchmarks of EXT4, Btrfs, and XFS on the Linux 2.6.39 kernel were just published this morning, an interesting change was just made for the next Linux kernel that will affect many of the file-systems living within the kernel. For what will be the Linux 2.6.40 kernel, or rather the Linux 3.0 kernel is the finally-merged support for CleanCache.

The CleanCache patch-set began as part of the Transcedent Memory patch-set more than one year ago (and discussed long before that), but with Linux 2.6.40/3.0 it's finally being merged. In fact, the patches just hit the Linus Torvalds Git tree in the past couple of hours. The documentation describes this CleanCache feature as:
This patchset introduces cleancache, an optional new feature exposed by the VFS layer that potentially dramatically increases page cache effectiveness for many workloads in many environments at a negligible cost. It does this by providing an interface to transcendent memory, which is memory/storage that is not otherwise visible to and/or directly addressable by the kernel.

Instead of being discarded, hooks in the reclaim code "put" clean pages to cleancache. Filesystems that "opt-in" may "get" pages from cleancache that were previously put, but pages in cleancache are "ephemeral", meaning they may disappear at any time. And the size of cleancache is entirely dynamic and unknowable to the kernel.

There's also this documentation file in the kernel for those wishing to learn more of the technical and implementation details. For the rest, CleanCache simply is designed to offer faster file-system performance. In particular, when there is high memory pressure there should be sizable improvements and for most workloads. "Basically cleancache replaces I/O with memory-copy-CPU-overhead; on older single-core systems with slow memory-copy speeds, cleancache has little value, but in newer multicore machines, especially consolidated/virtualized machines, it has great value."

As part of the push into the linux-2.6.git tree today, there is CleanCache support for the EXT3, EXT4, Btrfs, and OCFS2 file-systems. Other file-systems will also likely be supported in the future. Within the Xen area is also a CleanCache shim to the Transcendent Memory.

It should come as no surprise, but Linux CleanCache benchmarks will be published on Phoronix quite soon.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. Even With Re-Clocking, Nouveau Remains Behind NVIDIA's Proprietary Linux Driver
  2. The Power Consumption & Efficiency Of Open-Source GPU Drivers
  3. AMD R600g/RadeonSI Performance On Linux 3.16 With Mesa 10.3-devel
  4. Intel Pentium G3258 On Linux
Latest Linux Articles
  1. AMD Catalyst 14.6 Does Slightly Better With APITest OpenGL Tests
  2. Updated Source Engine Benchmarks On The Latest AMD/NVIDIA Linux Drivers
  3. Nouveau vs. Radeon vs. Intel Tests On Linux 3.16, Mesa 10.3-devel
  4. KVM Benchmarks On Ubuntu 14.10
Latest Linux News
  1. Builder: A New Development IDE Being Built For GNOME
  2. GDB 7.8 Betters Python Scripting, Adds Guile Support
  3. GNOME's GTK+ Is Still Striving For A Scene Graph, Canvas API
  4. Unreal Tournament Looks Great For Team Deathmatch
  5. LibreOffice 4.3 Released With Many Exciting Changes
  6. GNOME/GTK On Wayland Gains Focus At GUADEC
  7. GNOME Stakeholders Take Issue With Groupon Over their Gnome
  8. GStreamer VA-API Plug-In Update Adds New Features
  9. Qt 5.4 Going Into Feature Freeze Next Week With Exciting Changes
  10. OpenSUSE Factory Turns Into Rolling Release Distribution
Latest Forum Discussions
  1. Grand Theft Auto Running On Direct3D Natively On Linux Shows Gallium3D Potential
  2. Open-source drivers on ATI R7 260X
  3. AMD Athlon 5350 APU On Linux
  4. Debian + radeonsi
  5. Linus Torvalds On GCC 4.9: Pure & Utter Crap
  6. Updated and Optimized Ubuntu Free Graphics Drivers
  7. List of Linux friendly Kickstarter projects
  8. Porting Mesa to the Playstation 2